1,721,111 research outputs found
Investigating the efficiency of hybrid architectures for agricultural tractors using real-world farming data
Full text linkIn 2020, the European Commission (EC) approved the European Green Deal, which is an ambitious package of measures that aim to transform Europe into a climate-neutral area. Agricultural machinery in Europe produces around 70 million tons of CO2 emissions each year. Industry and researchers are currently investigating hybrid powertrains to significantly reduce CO2 emissions. This paper aims to investigate two hybrid powertrain architectures and report the benefits to farmers of such solutions using real-world data. Real-world data were collected using a Controller Area Network (CAN-BUS) data logger on a row-crop tractor with an engine power of 158 kW. Engine and transmission operating parameters were recorded for more than two years of field use. Data were first classified into tasks and then a series of inefficiency indices were defined. The operational inefficiency of each task type was then identified. Two hybrid powertrain architectures were evaluated using load point shifting principles. These were electric power take-off (ePTO) and plug-in P4 architecture. The hybrid architecture with the greatest benefits was the plug-in P4 powertrain, which achieved cost and CO2 savings of 7.2 % and 9.5 %, respectively. In the future, as the proportion of electricity from renewable sources increases, greater benefits could be achieved. On the other hand, the ePTO architecture permits to achieve a lower fuel saving, below than 2 %, but with a simpler technology
Short-Training Damage Detection Method for Axially Loaded Beams Subject to Seasonal Thermal Variations
No full textVibration-based damage features are widely adopted in the field of structural health monitoring (SHM), and particularly in the monitoring of axially loaded beams, due to their high sensitivity to damage-related changes in structural properties. However, changes in environmental and operating conditions often cause damage feature variations which can mask any possible change due to damage, thus strongly affecting the effectiveness of the monitoring strategy. Most of the approaches proposed to tackle this problem rely on the availability of a wide training dataset, accounting for the most part of the damage feature variability due to environmental and operating conditions. These approaches are reliable when a complete training set is available, and this represents a significant limitation in applications where only a short training set can be used. This often occurs when SHM systems aim at monitoring the health state of an already existing and possibly already damaged structure (e.g., tie-rods in historical buildings), or for systems which can undergo rapid deterioration. To overcome this limit, this work proposes a new damage index not affected by environmental conditions and able to properly detect system damages, even in case of short training set. The proposed index is based on the principal component analysis (PCA) of vibration-based damage features. PCA is shown to allow for a simple filtering procedure of the operating and environmental effects on the damage feature, thus avoiding any dependence on the extent of the training set. The proposed index effectiveness is shown through both simulated and experimental case studies related to an axially loaded beam-like structure, and it is compared with a Mahalanobis square distance-based index, as a reference. The obtained results highlight the capability of the proposed index in filtering out the temperature effects on a multivariate damage feature composed of eigenfrequencies, in case of both short and long training set. Moreover, the proposed PCA-based strategy is shown to outperform the benchmark one, both in terms of temperature dependency and damage sensitivity
A short-training method for monitoring axially-loaded beams in presence of unknown and large thermal variations
No full textThis paper deals with the problem of structural health monitoring of tie-rods, which undergo to large changes of eigenfrequencies when temperature changes because of the consequent change of the axial load. An approach for shortening the training period of the monitoring algorithm is proposed, relying on principal component analysis. This new method is compared to a state-of-the-art algorithm to evidence its strengths
The parkin gene is not a major susceptibility locus for typical late-onset Parkinson's disease
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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